At issue is an engine belt idler pulley bolt, which may not have been torqued to the proper value during engine assembly. As a result, the bolt can work loose, creating undesired bending stress from the pulley assembly and potentially shearing off the bolt.
Should this occur, a driver would experience a loss of power steering, increasing the effort required to control the vehicle. Since the belt also drives the alternator, failure would trigger a “Charging Malfunction” warning light on the instrument cluster.
BMW has seen multiple instances of in-field failures, most occurring in cold climates (which create additional friction on the idler pulley), though no accidents or injuries have been reported.
The recall is expected to begin in January of 2013, and BMW will notify affected owners. Dealers will replace the idler pulley bolt (coated with thread lock) and torque to the corrected value at no charge to owners. Owners of affected vehicles who have previously paid for such repairs may be eligible for a refund under the terms of this recall.
Those with questions or concerns can reach BMW’s customer service hotline at (800) 525-7417, or the National Highway Traffic Safety Administration’s Vehicle Safety Hotline at (888) 327-4236.